Liquid detergent composition

ABSTRACT

DISCLOSED HEREIN ARE STABLE TWO-PHASE LIQUID DETERGENT EMULSIONS THAT MAINTAIN STABILITY WITHOUT THE USE OF ADDITIONAL STABILIZING AGENTS. THESE AUTOSTABILIZED EMULSIONS ARE MADE UP OF ANIONIC, ZWITTERIONIC OR SIMIPOLAR COMPOUNDS, ELECTROLLYTES, ALCOHOLS AND WATER. AUTOSTABILIZED EMULSIONS ARE CAPABLE OF SUPPORTING WATER-INSOLUBLE PARTICULATE MATERIAL.

United States Patent Oflice 3,813,349 Patented May 28, 1974 US. Cl.252-526 2 Claims ABSTRACT OF THE DISCLOSURE Disclosed herein are stabletwo-phase liquid detergent emulsions that maintain stability without theuse of additional stabilizing agents. These autostabilized emulsions aremade up of anionic, zwitterionic or simipolar compounds, electrolytes,alcohols and water. Autostabilized emulsions are capable of supportingwater-insoluble particulate material.

This is a continuation of application Ser. No. 888,862, filed Dec. 29,1969, and now abandoned.

BACKGROUND OF THE INVENTION There is an ever increasing demand forliquid detergent compositions that are useful as, e.g., liquid scouringcleanser compositions or as liquid abrasive cleaner compositions. Theseliquid detergent cleaning compositions are provided in a convenientform. The compositions of this invention are especially formulated forthe above expressed cleaning applications.

To obtain optimum cleaning ability and wide consumer acceptance,detergent compositions of this invention must be homogeneous and easilypourable. The above compositions should maintain their homogeneityduring ordinary periods of storage and use. It is highly desirable thatthe formulation of the invetnion exhibits Bingham plasticcharacteristics, i.e., exhibit a substantial yield value to keep theparticulate materials suspended.

This invention relates to the formulation of stable two phase liquiddetergent emulsions, called autostabilized emulsions, capable ofsupporting water-insoluble particulates which have utility as, e.g.,hard surface cleaners. Autostabilized emulsions can be formed withoutthe use of additional stabilizing agents. Due to the addition ofalcohol, the autostabilized emulsions can support higher electrolytelevels than previously known two-phase emulsion compositions, making theautostabilized emulsions much more desirable as, e.g., hard surfacecleaners.

SUMMARY OF THE INVENTION The formulations of this invention, having theabovedescribed utility, are novel, stable two-phase liquid detergentemulsions, referred to as autostabilized emulsions.

An object of this invention is to formulate autostabilized two-phaseliquid detergent emulsions, i.e., emulsions that are stabilized withoutthe use of hydrotropes or other stabilizing agents, capable ofsupporting water-insoluble particulates.

A further object of this invention is to formulate autostabilizedemulsions that are useful, e.g., in liquid scouring cleansercompositions or as liquid abrasive cleaner compositions.

THE PRIOR ART Many of the components used in the present invention arewell known in combination in the detergent art on two-phase liquiddetergent emulsions. This is pointed out in U.S. Pats. 2,999,068,3,232,878 and 3,281,267.

In US. Pats. 3,272,753, 3,332,875, 3,179,599, 3,035,- 982 and 3,179,598,the use of ethanol in various liquid detergent compositions isdisclosed. Ethanol, as used in the art, is a solvent that allows thecombination of components in a more stable solution. The art does notsuggest that as an additive ethanol allows an increase in electrolytecontent of an already stable two-phase emulsion as in the presentinvention. Thus, although the art teaches some stable two-phaseemulsions with various components that are similar to those used in thepresent invention, the art fails to each the present invention whichcontains very specific components and composition ranges and whichprovides for autostabilized two-phase emulsions capable of supportingwater-insoluble particulate material and unexpectedly large additions ofelectrolyte for use in, e.g., liquid scouring cleanser compositions andliquid abrasive cleaner compositions.

DETAILED DESCRIPTION OF THE INVENTION The liquid detergent compositionsof this invention are autostabilized, two-phase, liquid detergentemulsions capable of supporting water-insoluble particulate material,said autostabilized emulsions consisting essentially of:

(1) from about 4% to about 28% by weight of:

(a) an anionic synthetic detergent surfactant having the general formulawherein R and R are staight chain alkyl radicals containing from about10 to about 16 carbon atoms and M is a cation selected from the groupconsisting of potassium, sodium, ammonium, monoethanolammonium,diethanolammonium, and triethanolammonium cations; and

(b) a zwitterionic quaternary ammonio synthetic detergent surfactanthaving the general formula wherein R is an alkyl radical containing fromabout 10 to about 16 carbon atoms, and R is selected from the groupconsisting of hydrogen and hydroxyl; or (c) a semipolar surfactanthaving the general formula wherein the ratio of zwitterionic orsemipolar to anionic surfactants is from about 2:1 to about 1:3.

The individual components of the autostabilized emulsions of thisinvention are anionic detergent, semipolar detergent or zwitterionicsynthetic detergent, electrolyte, alcohol and water. Optional componentsinclude minor ingredients which have aesthetic value or which improvethe effectiveness of the autostabiilzed emulsions. As a preferredembodiment, insoluble particulate material can be added to theautostabiized emulsions of this invention, since all of theautostabilized emulsions of this invention are capable of suspendinginsoluble particulate materials.

In the autostabilized emulsions of this emulsion, it has been discoveredthat the surfactants must be a mixture of a semipolar or zwitterionicsurfactant with an anionic surfactant in specific proportions, i.e., aratio of about 2:1 to about 1:3 respectively and in a specific amount,i.e., from about 4% to about 28% by weight of the autostabilizedemulsion compositions. Anionic surfactants and zwitterionic or semipolarsurfactants, when used separately, will not provide a stable support forinsoluble particulate materials. However, when they are used together asspecified below, they unexpectedly cooperate to provide a stable mediumwith a yield value that will support insoluble particulate material.

The total amount of zwitterionic or semipolar and anionic surfactants,i.e., from about 4% to about 28% by weight of the composition, and therelative amount in which the above surfactants are present in theautostabilized emulsion compositions of this invention, i.e., a ratio ofzwitterionic or semipolar to anionic surfactant of about 2:1 to about1:3, is more important in the practice of this invention than the exactamount of each surfactant in the autostabilized emulsions.

While the exact amount of each detergent surfactant is of littlesignificance, the total amount of the surfactants is important. Thetotal amount of surfactant used in an autostabilized emulsion determinesthe yield value and the ability to dissolve grease and dirt. If there isan excessive amount of total surfactant present in the autostabilizedemulsion, i.e., above about 28% by weight of the composition, theautostabilized emulsion becomes too thick and unmanageable.

The relative amount of zwitterionic or semipolar to anionic detergentsurfactants, i.e., a weight ratio of zwitterionic or semipolar toanionic surfactant, sharply affects the ability of the auto stabilizedemulsion to support insoluble particulate material. When the ratio ofzwitterionic or semipolar to anionic surfactant falls within the properrelative amount, i.e., a ratio of about 2: 1 to about 1:3, theautostabilized emulsions of this invention have excellent yield values,and they maintain phase stability. It is preferred that the ratio ofzwitterionic or semipolar to anionic surfactant be about 1:1. The exactvalue of this ratio depends on other materials present in theautostabilized emulsions.

It has been discovered that only certain members of each class arefunctional. Two anionic detergnts provide the necessary emulsionstability; these detergents are alkyl glyceryl ether sulfonate andalkylbenzene sulfonate. Two zwitterionic synthetic detergents providethe necessary emulsion stability; these detergents are hydroxy ammoniopropane sulfonate and ammonio propane sulfonate. One semipolar detergentalternatively provides the necessary emulsion stability; this isalkyldimethylamine oxide. The semipolar detergent, i.e., alkylidimethylamine oxide is more preferred over the zwitterionicdetergents in combination with the other components of theautostabilized emulsions of this invention.

From about 10% to about 20% of the finished composition is polyvalentelectrolyte or builder. Only the addition of a lower alcohol containing1 to about 5 carbon atoms, preferably ethanol, in an amount from about2% to about 9%, preferably about 5%, allows this relatively high amountof electrolyte to be used with no effect on stability. The preferredamount of electrolyte as used in the compositions of this invention isabout 15% by weight of the composition. This increase in electrolytecontent assists in maximizing stability and increasing the cleaningcharacteristics of the autostabilized emulsion. Various electrolytes canbe used, e.g., tetrapotassium 4 pyrophosphate, nitrolotriacetate andethane-l-hydroxy- 1,1-diphosphonate.

Tetrapotassium pyrophosphate is preferred to other electrolytes becauseof its good cleaning characteristics and excellent solubilitycharacteristics. The liquid detergent compositions built withtetrapotassiurn pyrophos phate also exhibit excellent stabilitycharacteristics over a wide range of temperatures.

Although other electrolytes may be used, their operating region in whichphase stability is maintained is relatively small. The operating regionvaries for each specific combination of components. The addition oflower alcohols by expanding the operating region of autostabilizedemulsions allows the addition of higher levels of electrolyte withoutthe normally resulting instability that occurs if higher amounts ofbuilder are added Without the lower alcohol. In previous compositions,only from 1% to 10% electrolyte could be used if stability was to bemaintained. In this invention, with lower alcohol addition, 10% to 20%is used making autostabilized emulsions more effective as, e.g., hardsurface cleaners. An operating region in the range wherein the differentcomponents in the autostabilized emulsion can be used in various amountsand phase stability is still maintained.

The balance of the composition is water. It is preferred that from about30% to about 50% by weight of the finished composition be water when theinsoluble particulate material is added to the autostabilized emulsionsto optimize yield values and cleaning characteristics of the finishedproduct. The pH of the compositions is in the range from about 7 toabout 12, preferably from about 9 to about 11.

In the practice of this invention, from 5% to about 75% of thecomposition can be insoluble particulate material. It is preferred,however, that from about 40% to about 50% by weight of the finishedcomposition be insoluble particulate material.

Within the preferred range of insoluble particulate material (about 40%to about 50% it is preferred that about 4% to about 20% of thesupporting medium be detergent surfactants. At higher than the specifieddetergent concentrations, the combined detergent and insolubleparticulate materials make the compositions too thick to be manageable;at lower than the specified detergent concentrations there is not enoughdetergent to provide sufficient yield value to support the insolubleparticulate material. The upper limit on combined detergent andinsoluble particulate material is a functional one, and is bestexpressed in terms of apparent viscosity. The detergent compositions ofthe preferred embodiment of this invention must have apparent viscositybelow about 12,000 centipoises. It is preferred that the apparentviscosity be below about 10,000 centipoises. As used herein andelsewhere in this specification, apparent viscosity means the valueobtained with a Brookfield viscometer, Model LVF, using spindle number 3at 12 r.p.m. At lower (below 40%) insoluble particulate materialconcentrations, the concentration of total detergent in the supportingmedium becomes less important.

The insoluble, particulate material which can be utilized in thisinvention can comprise abrasives, bactericides, or other insolubleparticulate material having a particle size diameter ranging from about1 to about 200 microns and a density of from about 0.5 to about 5.0. Itis preferred that the diameter of the particles range from about 2microns to about 60 microns and that the density range from about 1.0 toabout 2.8. The insoluble particulate materials which can be utilized inthis invention include, but are not limited to, quartz, pumice,pumicite, talc, silica, sand, calcium carbonate, china clay, zirconinumsilicate, bentonite, diatomaceous earth, whiting, feldspar, and aluminumoxide. Silica is the preferred insoluble particulate material for useherein.

Minor amounts of materials which make the composition of this inventionmore attractive or more effective can be added, e.g., soluble sodiumcarboxymethylcellulose, tarnish inhibitors such as benzotriazole orethylenethiourea, brighteners, bleaches, fiuorescers, dyes, bluingagents, perfumes, bactericides and corrosion inhibitors,

it contains upwards of 75% of the total electrolyte. Neat is poorlyconductive, more or less 3,000 ,umhos/cm. The stable emulsions haveconductivities less than 25,000 pmhos/cm. instead of the greater than80,000 mhos/cm.

if they do not significantly alter the excellent physical 5 expected fora lye continuous emulsion. Mhos/cm. properties of this composition.means micro ohms per centimeter, which is a unit of In Bingham plastics,insoluble particulate material is conductivity.) suspended because thestress imposed by the particles The following example is givenadditionally to illustrate does not exceed the yield value of theliquid. of course, the nature of the invention and it will be understoodthat if the yield value of the supporting medium should dethe inventionis not limited thereto. In this example, as crease sutficiently for anyreason, the particles would no in the specification, and claims,proportions indicated are longer be suspended. This could be caused, forexample, percent by weight unless otherwise specified.

EXAMPLE I Percent Coconut Linear alkylcoconut Tetrapo- Totaldimethylalkyltassium Phases suramine benzene pyrophos- Etha- Samplefactant oxide sulfonate phate 1101 B20 Neat/Niger/Lye 1 5 3.06 1.94 10 5Balance- X X 2 5 3.06 1.94 5 ...do.--.. X X 3... 5 3.06 1.94 5...do--.--X X 4 10 s. 12 ass 10 5 ..do..... X X 5... 10 6.12 3.83 15 5-..do X Xs... 10 6.12 3.88 20 5 ...do..... X X

by a physical or chemical change in the supporting The example showsvarious formulations of this inmedium, e.g., if the autostabilizedemulsion settles into vention by demonstrating that stable neat-lyeformulalayers upon standing, the yield value can be lost temtions remainstable with increased electrolyte addition of porarily. The originalcomposition with its yield value up to about 20% where ethanol is added,e.g., sample can be reconstituted by mixing. If a chemical reactionnumber 3, shows a neat-lye emulsion with an electrolyte either consumesa vital component or produces a damcontent of 20% by weight of thecomposition. These aging one, the loss of yield value can be permanent.formulations were found to have excellent cleaning Hydrotropes such assodium or potassium xylenecharacteristics and the ability to supportwater-insoluble sulfonate, toluenesulfonate, or benzenesulfonate, shouldparticulates that makes them useful as, e.g., hard surnot be present inthese compositions. Even very small face cleaners. More specifically,silica is added to each amounts of these hydrotropes solubilize thediscrete phase of the compositions of the above example in an amountinto the continuous phase. Thus, the detergent composiof 45% by weightof the compositions. The compositions tion can become a one-phasesolution and loses its Bing- 0f the above example remain autostabilizedemulsions and ham plastic characteristics with resultant settling of thepport the silica. insoluble particulate material. The composition, inthis What is claimed is: condition, is aesthetically undesirable and notsalable on All autostabilized, two-Phase ydrotropeand soapb il consumermarket or h i d i l market free liquid abrasive detergent emulsioncontaining a mix- Also to be avoided are soaps, amides, and othermatetllre Surfactants in a Proportion that coopefafivfily rials whichare presently or potentially solubilizing p a Stable medium having ayield Value capable of agents, or which combine with water hardnessions. l lfp 10501111316 pflfliclllate lqatefial, Said s a- Thecompositions of this invention are formulated by blhzed 6111111510115conslstlng essentlally of mixing the components together in the amountsdesired. from about 4% to about 23% y Weight of a The order of mixingdoes not afli'ect the stability of the tllrq 0f emulsion. Any of thedesired optional ingredients can then a 1111631 alkyl benzene sulphonatehaving the be added. general formula Ultracentrifuging is used in thefollowing example to completely separate the phases in theautostabilized emulsions and to determine the relative proportions ofthe bases resent. The autostabilized emulsions all contain d a neatphase and a lye phase. The autostabilized h f IS abstralght cham alkylradlcal emulsions are believed to be lye in neat emulsions with conalmpg m 2 out 10 to 16 carbon atoms and M 18 a cation selected from thegroup conthe lye phase being the dispersed phase. This 1s unsisting ofpotassium, sodium, ammomum, expected smce the lye 15 generally q or lessmonoethanolammonium, diethanolammonium 75% of the total composition byvolume. Evidence for and triethanolammonium cations and it thfiory 1stwofold. The r?latw.ely poor dl.spersl' (ii) a semipolar surfactanthaving the general bility of these autostabilized emulsions is expectedif neat formula phase is continuous since the neat phase would have togo through middle phase in the process of dissolving. If the lye phaseis continuous the emulsions disperse very 0 well in water. However, itis discovered that, in fact, H autostabilized emulsions have poordispersibility. Dispersibility improves, however, as the amount ofsurfactant h i R i an alkyl radical containing f is lessened in theautostabilized emulsions. Thus, in the about 10 to 1 carbon atoms;practice of this invention, it has been discovered that (b) f 10% tabout 20% b i h f a l emulsions maximize their dispersibility andcleaning charal nt electrolyte selected from the group consistingactefistics by the use of the Particular cQIIIPOIIGIHS and oftetrapotassium pyrophosphate, nitrilotriacetate particular proportionsof each component in the autoand ethane-l-hydroxy-1,1-diphosphonate;stabilized emulsions disclosed. (2) Conductivity meas- (c) from about 2%to about 9% of a lower alcohol urements gave further evidence that thestable emulsions containing from 1 to about 5 carbon atoms; are lye inneat rather than neat in lye. Lye is very con- (d) from about 5% toabout 75% by weight of an ductive greater than 100,000 ,umhos/cm. asexpected since abrasive insoluble particulate material having a particlesize diameter ranging from about 1 to about 200 microns and a density offrom about 0.5 to about and (e) the balance being water; wherein theratio by weight of the amine oxide to the alkyl benzene sulphonate isfrom about 1.6:1 to about 1:1.

2. An autostabilized, two-phase hydrotropeand soap free liquid abrasivedetergent emulsion containing a mixture of surfactants in a proportionthat cooperatively provides a stable medium having a yield value capableof supporting insoluble particulate material, said autostabilizedemulsions consisting essentially of (a) from about 5% to about by weightof a mixture of sodium coconut linear alkyl benzene sulphonate andcoconut alkyl dimethyl amine oxide, wherein the ratio by weight of saidamine oxide to said alkyl benzene sulphonate is in the range of about1.6:! to about 1.521;

(b) from about 10% to about by weight of a polyvalent electrolyteselected from the group consisting of tetrapotassium pyrophosphate,nitrilotriacetate and ethane-l-hydroxy-l,l-diphosphonate;

(c) from about 2% to about 9% of a lower alcohol containing from 1 toabout 5 carbon atoms;

(d) about by weight of silica having a particle References Cited and 5(c) the balance being water.

UNITED STATES PATENTS 2,877,188 3/1959 Kruxnrei 252-558 X 10 2,999,0689/1961 Pilcher et a1 252-547 X 3,101,324 8/1963 Wixon 252-558 X3,346,873 10/1967 Herrmann 252-528 X 3,392,121 7/ 1968 George 252-527 X3,453,144 7/ 1969 Morgan et a1. 252-538 X 15 3,520,818 7/1970 Cambre252- X 3,522,185 7/1970 Cambre 252-119 X 3,579,456 I 5/1971 Cambre 252-X 3,630,922 12/1971 McClain et a1. 252-528 X 20 LEON D. ROSDOL,

Primary Examiner H. A. PITLICK, Assistant Examiner

